user: Question: What is the minimum gross tonnage of the Munich? 
Columns: ['Ships name', 'Entered service', 'Ended service', 'Gross Tonnage', 'Type of Vessel']
Types: ['text', 'text', 'text', 'real', 'text']
Sample row: ['Avalon', '13 June 1864', '1866', 613.0, 'Paddle steamer']
SQL:

assistant: SELECT MIN("Gross Tonnage") FROM "Table" WHERE "Ships name" = 'Munich';