CREATE TABLE table_11111116_8 (us_viewers__million_ VARCHAR, original_air_date VARCHAR)

How many millions of U.S. viewers watched the episode that first aired on March 31, 2013?
SELECT us_viewers__million_ FROM table_11111116_8 WHERE original_air_date = "March 31, 2013"
SELECT "us_viewers__million_" FROM "table_11111116_8" WHERE "March 31, 2013" = "original_air_date"