Table: tv_episodes_6
Columns: series
title
directed_by
written_by
original_air_date
production_code
u_s_viewers_million

Question: What is the original air date when the u.s. viewers in millions was 5.39?
SQL: SELECT "original_air_date" FROM tv_episodes_6 WHERE "u_s_viewers_million" = '5.39'

Question: What is the title of the series # 8?
SQL: SELECT "title" FROM tv_episodes_6 WHERE "series" = 8

Question: What is the highest series # directed by ken whittingham?
SQL: SELECT MAX("series") FROM tv_episodes_6 WHERE "directed_by" = 'Ken Whittingham'

Question: How many episodes had a production code 120?
SQL: SELECT COUNT("series") FROM tv_episodes_6 WHERE "production_code" = 120