user: Question: What is the constructor where the circuit is Silverstone?
Columns: ['Race Name', 'Circuit', 'Date', 'Winning driver', 'Constructor', 'Report']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['VI Glover Trophy', 'Goodwood', '7 April', 'Mike Hawthorn', 'Ferrari', 'Report']
SQL:

assistant: SELECT "Constructor" FROM "Table" WHERE "Circuit" = 'Silverstone';