user: Question: What is the date where the tonnage is larger than 5754 and the ship was sunk by U-305?
Columns: ['Date', 'Name', 'Flag', 'Tonnage (GRT)', 'Sunk by']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['16/17 March 1943', 'Kingsbury', 'United Kingdom', 4898.0, 'U-338']
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Tonnage (GRT)" > 5754.0 AND "Sunk by" = 'U-305';