Table: series_info
Columns: no_in_series
title
directed_by
written_by
original_air_date
production_code
u_s_viewers_millions

Question: What is the production code of the episode directed by David Solomon? 
SQL: SELECT "production_code" FROM series_info WHERE "directed_by" = 'David Solomon'

Question: Who wrote the episode with the production code of BN103? 
SQL: SELECT "written_by" FROM series_info WHERE "production_code" = 'BN103'

Question: What was the original air date of the episode that had 4.08 million U.S. viewers? 
SQL: SELECT "original_air_date" FROM series_info WHERE "u_s_viewers_millions" = '4.08'