user: Question: what is the least tonnage grt when the nationality is British and the ship is Kidalton?
Columns: ['Date', 'Ship', 'Type', 'Nationality', 'Tonnage GRT', 'Fate']
Types: ['text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['5.12.1914', 'Charcas', 'Freighter', 'British', 5067.0, 'Sunk']
SQL:

assistant: SELECT MIN("Tonnage GRT") FROM "Table" WHERE "Nationality" = 'British' AND "Ship" = 'Kidalton';