Giving Userwarning for labelling columns in 'name' attribute of read_csv
#### Code Sample, a copy-pastable example if possible

```python

df= pd.read_csv(filename, sep='\t',names=['PID','WORD','-','POS','-','-','PID-WITH','RELATION','-','-'])


```
#### Problem description
The input csv file in my case is actually a tab separated file.
I am getting a UserWarning after following the syntax provided in the documentation. This is indicatinf me, that I will get error in future. What will be that?

#### Expected Output

No warnings should occur

<details>

/lib/python3.6/site-packages/pandas/io/parsers.py:678: UserWarning: Duplicate names specified. This will raise an error in the future.
  return _read(filepath_or_buffer, kwds)


</details>
