user: Question: What's the lowest goal difference when the position is higher than 16?
Columns: ['Position', 'Club', 'Played', 'Points', 'Wins', 'Draws', 'Losses', 'Goals for', 'Goals against', 'Goal Difference']
Types: ['real', 'text', 'real', 'real', 'real', 'real', 'real', 'real', 'real', 'real']
Sample row: [1.0, 'UD Las Palmas', 30.0, 40.0, 17.0, 6.0, 7.0, 45.0, 25.0, 20.0]
SQL:

assistant: SELECT MIN("Goal Difference") FROM "Table" WHERE "Position" > 16.0;