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_33 (prr_class VARCHAR, wheel_arrangement VARCHAR)
### Question:
What PRR class has a Wheel arrangement of a1a-a1a?
### Answer:
SELECT prr_class FROM table_name_33 WHERE wheel_arrangement = "a1a-a1a"