user: Question: How many colleges have a DB position?
Columns: ['Pick #', 'CFL Team', 'Player', 'Position', 'College']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [27.0, 'Hamilton Tiger-Cats', 'Connor Healey', 'DB', 'Wilfrid Laurier']
SQL:

assistant: SELECT COUNT("College") FROM "Table" WHERE "Position" = 'DB';