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_2409041_2 (original_air_date VARCHAR, no_in_series VARCHAR)
### Question:
When 21 is the number in series what is the air date?
### Answer:
SELECT original_air_date FROM table_2409041_2 WHERE no_in_series = 21