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_24 (on_air_id VARCHAR, frequency VARCHAR, purpose VARCHAR)
### Question:
What is the On-air ID with the frequency of 105.9, and purpose of commercial?
### Answer:
SELECT on_air_id FROM table_name_24 WHERE frequency = "105.9" AND purpose = "commercial"