Table: episode_data_4
Columns: no_in_series
no_in_season
title
directed_by
written_by
original_air_date
production_code

Question: If the production code is 6.18, what was the episode title?
SQL: SELECT "title" FROM episode_data_4 WHERE "production_code" = '6.18'

Question: If the original air date January 19, 1992, who was the episode directed by?
SQL: SELECT "directed_by" FROM episode_data_4 WHERE "original_air_date" = 'January 19, 1992'