user: Question: What is the Tonnage of the ship from Canada?
Columns: ['Date', 'Name of ship', 'Flag', 'Tonnage', 'Fate']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['3 February1941', 'Empire Citizen', 'United Kingdom', 4683.0, 'sunk at']
SQL:

assistant: SELECT "Tonnage" FROM "Table" WHERE "Flag" = 'Canada';