CREATE TABLE table_29803475_2 (original_air_date VARCHAR, us_viewers__million_ VARCHAR)

What is every original air date with U.S. viewers of 0.23 million?
SELECT original_air_date FROM table_29803475_2 WHERE us_viewers__million_ = "0.23"
SELECT "original_air_date" FROM "table_29803475_2" WHERE "0.23" = "us_viewers__million_"