Table: episodes_table_13
Columns: no_in_season
no_disc
title
directed_by
written_by
original_air_date

Question: How many original air dates were there for episode 17?
SQL: SELECT COUNT("original_air_date") FROM episodes_table_13 WHERE "no_in_season" = 17

Question: When did the episode titled "Prisoners" first air?
SQL: SELECT "original_air_date" FROM episodes_table_13 WHERE "title" = '"Prisoners"'