Table: tv_episode_data_21
Columns: no_in_series
no_in_season
title
directed_by
written_by
original_air_date
prod_code
u_s_viewers_millions

Question: who directed the episode that 6.3 million u.s. viewers saw?
SQL: SELECT "directed_by" FROM tv_episode_data_21 WHERE "u_s_viewers_millions" = '6.3'

Question: how man episodes in the season were titled "that's so sonny"?
SQL: SELECT COUNT("no_in_season") FROM tv_episode_data_21 WHERE "title" = '"That''s So Sonny"'