Question: How many millions of U.S. viewers watched the episode that first aired on March 31, 2013?
Schema: create table table_11111116_8 (us_viewers__million_ varchar, original_air_date varchar, PRIMARY KEY (us_viewers__million_))
SQL: select us_viewers__million_ from table_11111116_8 where original_air_date = "march 31, 2013"