CREATE TABLE table_name_21 (airing_date VARCHAR, genre VARCHAR, number_of_episodes VARCHAR)

What is the airing date for a modern drama with more than 21 episodes?
SELECT airing_date FROM table_name_21 WHERE genre = "modern drama" AND number_of_episodes > 21
SELECT "airing_date" FROM "table_name_21" WHERE "genre" = "modern drama" AND "number_of_episodes" > 21