BUG: DataFrame from sqlalchemy 1.4 `Query` missing column headers
- [x] I have checked that this issue has not already been reported.

- [x] I have confirmed this bug exists on the latest version of pandas.

- [ ] (optional) I have confirmed this bug exists on the master branch of pandas.

---

**Note**: Please read [this guide](https://matthewrocklin.com/blog/work/2018/02/28/minimal-bug-reports) detailing how to provide the necessary information for us to reproduce your bug.

#### Code Sample, a copy-pastable example

```py
# Your code here
from sqlalchemy import create_engine, Table, Column, Integer, String
from sqlalchemy.orm import sessionmaker
from sqlalchemy.ext.declarative import declarative_base
import pandas as pd
import sqlalchemy as sa

BaseModel = declarative_base()


class Test(BaseModel):
    __tablename__ = "test"
    id = Column(Integer, primary_key=True)
    foo = Column(String(50))


engine = create_engine("sqlite:///")
BaseModel.metadata.create_all(engine)
Session = sessionmaker(bind=engine)
session = Session()

df = pd.DataFrame({"id": [0, 1], "foo": ["hello", "world"]})
df.to_sql("test", con=engine, index=False, if_exists="replace")

session.commit()
foo = session.query(Test.id, Test.foo)
df = pd.DataFrame(foo)
session.close()
print(df)
assert list(df.columns) == ["id", "foo"]
```

#### Problem description

Coping from https://github.com/sqlalchemy/sqlalchemy/issues/6154. 
In sqlalchemy 1.4 `Query` returns `Row` objects that are no longer subclass of tuple, so they don't pass the `is_named_tuple` check, as mentioned by Mike here https://github.com/sqlalchemy/sqlalchemy/issues/6154#issuecomment-809441845

#### Expected Output

The colums are named `0,1` instead of `'id', 'foo'`

#### Output of ``pd.show_versions()``

<details>


INSTALLED VERSIONS
------------------
commit           : f2c8480af2f25efdbd803218b9d87980f416563e
python           : 3.8.8.final.0
python-bits      : 64
OS               : Windows
OS-release       : 10
Version          : 10.0.21337
machine          : AMD64
processor        : Intel64 Family 6 Model 60 Stepping 3, GenuineIntel
byteorder        : little
LC_ALL           : None
LANG             : None
LOCALE           : English_United Kingdom.1252

pandas           : 1.2.3
numpy            : 1.19.2
pytz             : 2019.3
dateutil         : 2.8.1
pip              : 21.0.1
setuptools       : 52.0.0.post20210125
Cython           : None
pytest           : 6.2.1
hypothesis       : None
sphinx           : 3.5.1
blosc            : None
feather          : None
xlsxwriter       : None
lxml.etree       : None
html5lib         : None
pymysql          : 0.9.3
psycopg2         : 2.8.6 (dt dec pq3 ext lo64)
jinja2           : 2.10.3
IPython          : 7.14.0
pandas_datareader: None
bs4              : None
bottleneck       : None
fsspec           : None
fastparquet      : None
gcsfs            : None
matplotlib       : None
numexpr          : None
odfpy            : None
openpyxl         : None
pandas_gbq       : None
pyarrow          : None
pyxlsb           : None
s3fs             : None
scipy            : None
sqlalchemy       : 1.4.4 (actually master)
tables           : None
tabulate         : None
xarray           : None
xlrd             : None
xlwt             : None
numba            : 0.52.0

</details>
