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"
### Context: CREATE TABLE table_28680377_2 (original_air_date VARCHAR, us_viewers__million_ VARCHAR) ### Question: What is the original air date of the episode that was watched by 0.88 million U.S. viewers?  ### Answer: SELECT original_air_date FROM table_28680377_2 WHERE us_viewers__million_ = "0.88"