user: Question: What is the production code for episode 31 in the series?
Columns: ['Series #', 'Season #', 'Title', 'Directed by', 'Written by', 'Original air date', 'Prod. code']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'real']
Sample row: [27.0, 1.0, '"The Triangle"', 'Jon Rosenbaum', 'Thomas W. Lynch', 'June25,2011', 201.0]
SQL:

assistant: SELECT "Prod. code" FROM "Table" WHERE "Series #" = 31.0;