user: Question: What's the lowest pick for a Defensive Back at Drake?
Columns: ['Pick', 'Round', 'Player', 'Position', 'School']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [22.0, '1', 'Ray Snell', 'Guard', 'Wisconsin']
SQL:

assistant: SELECT MIN("Pick") FROM "Table" WHERE "Position" = 'Defensive Back' AND "School" = 'Drake';