Table: episodes_4
Columns: no_in_series
no_in_season
title
directed_by
written_by
original_air_date

Question: name the title of the episode that ed sherin directed.
SQL: SELECT "title" FROM episodes_4 WHERE "directed_by" = 'Ed Sherin'

Question: the first episode in this season had what number in the series? 
SQL: SELECT MIN("no_in_series") FROM episodes_4