user: Question: When did Episode 6 first air with entrepreneur Guy Portelli?
Columns: ['Episode', 'First aired', 'Entrepreneur(s)', 'Company or product name', 'Money requested (£)', 'Description of product', 'Investing Dragon(s)']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Episode 1', '21 July 2008', 'Jamie Turner', 'Hamfatter', '75,000', 'A music band', 'Peter Jones']
SQL:

assistant: SELECT "First aired" FROM "Table" WHERE "Episode" = 'Episode 6' AND "Entrepreneur(s)" = 'Guy Portelli';