user: Question: Which Date has a Ship of Hallbjorg?
Columns: ['Date', 'Ship', 'Type', 'Nationality', 'Tonnage GRT']
Types: ['text', 'text', 'text', 'text', 'real']
Sample row: ['2 Dec 16', 'Voltaire', 'Cargo ship', 'United Kingdom', 8618.0]
SQL:

assistant: SELECT "Date" FROM "Table" WHERE "Ship" = 'Hallbjorg';