Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_21781578_2 ( original_air_date VARCHAR, season_no VARCHAR )

### Question ###
What was the original air date for season number 2?

### Accurate SQL ###

SELECT original_air_date FROM table_21781578_2 WHERE season_no = 2