user: Question: Which round was the circuit Assen
Columns: ['No', 'Date', 'Round', 'Circuit', 'Pole Position', 'Fastest Lap', 'Race Winner', 'Report']
Types: ['real', 'text', 'text', 'text', 'text', 'text', 'text', 'text']
Sample row: [1.0, '23 February', 'Qatar', 'Losail', 'Fabien Foret', 'Fabien Foret', 'Broc Parkes', 'Report']
SQL:

assistant: SELECT "Round" FROM "Table" WHERE "Circuit" = 'Assen';