Table: tv_episodes_9
Columns: no
col
title
directed_by
written_by
u_s_viewers_million
rank_week
original_air_date

Question: What is the original air date of the episode that had a week ranking of 21?
SQL: SELECT "original_air_date" FROM tv_episodes_9 WHERE "rank_week" = 21

Question: What was the week ranking of the episode written by Russel Friend & Garrett Lerner? 
SQL: SELECT "rank_week" FROM tv_episodes_9 WHERE "written_by" = 'Russel Friend & Garrett Lerner'

Question: What was the week ranking of the episode written by Thomas L. Moran and directed by Andrew Bernstein?
SQL: SELECT "rank_week" FROM tv_episodes_9 WHERE "written_by" = 'Thomas L. Moran' AND "directed_by" = 'Andrew Bernstein'