CREATE TABLE table_name_23 (episode_no VARCHAR, original_airdate VARCHAR)

What is the episode number of the episode that originally aired on February 4, 2008?
SELECT episode_no FROM table_name_23 WHERE original_airdate = "february 4, 2008"
SELECT "episode_no" FROM "table_name_23" WHERE "february 4, 2008" = "original_airdate"