user: Question: Name the fastest lap for Piquet Sports and Silverstone
Columns: ['Round', 'Circuit', 'Date', 'Pole Position', 'Fastest Lap', 'Winning driver', 'Winning team']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['1', 'Donington Park', '6 April', 'Jamie Green', 'Alan van der Merwe', 'Jamie Green', 'Carlin Motorsport']
SQL:

assistant: SELECT "Fastest Lap" FROM "Table" WHERE "Winning team" = 'Piquet Sports' AND "Circuit" = 'Silverstone';