What is the original air date of the episode that was watched by 0.88 million U.S. viewers?
CREATE TABLE table_28680377_2 (
    original_air_date VARCHAR,
    us_viewers__million_ VARCHAR
)
SELECT original_air_date FROM table_28680377_2 WHERE us_viewers__million_ = "0.88"
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the original air date of the episode that was watched by 0.88 million U.S. viewers? ### Input: CREATE TABLE table_28680377_2 (
    original_air_date VARCHAR,
    us_viewers__million_ VARCHAR
) ### Response: SELECT original_air_date FROM table_28680377_2 WHERE us_viewers__million_ = "0.88"