user: Question: How many production codes are there for "The Sub"?
Columns: ['No. in series', 'No. in season', 'Title', 'Directed by', 'Written by', 'Original air date', 'Production code']
Types: ['real', 'real', 'text', 'text', 'text', 'text', 'real']
Sample row: [53.0, 1.0, '"First Day of School"', 'James Widdoes', 'Kathy Ann Stumpe', 'September24,2004', 302.0]
SQL:

assistant: SELECT COUNT("Production code") FROM "Table" WHERE "Title" = '"The Sub"';