Below is an context that describes a sql query, paired with an question that provides further information. Write an answer that appropriately completes the request.  # noqa: E501
### Context:
CREATE TABLE table_name_72 (class VARCHAR, year VARCHAR, chassis VARCHAR)
### Question:
Which class has a year prior to 2011 and audi r15 tdi as the chassis?
### Answer:
SELECT class FROM table_name_72 WHERE year < 2011 AND chassis = "audi r15 tdi"