user: Question: What is the production code of the episode before season 8, with a series number less than 31, and aired on September 21, 1995?
Columns: ['Series #', 'Season #', 'Title', 'Directed by', 'Original air date', 'Production code']
Types: ['real', 'real', 'text', 'text', 'text', 'text']
Sample row: [27.0, 1.0, '"High on the Hog"', 'Frederick K. Keller', 'August 31, 1995', 'K0503']
SQL:

assistant: SELECT "Production code" FROM "Table" WHERE "Season #" < 8.0 AND "Series #" < 31.0 AND "Original air date" = 'September 21, 1995';