user: Question: What is the vote number when immunity listed as David and reward is listed as None?
Columns: ['First air date', 'Reward', 'Immunity', 'Eliminated', 'Vote', 'Finish']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['September 12, 2010', 'North Team', 'North Team', 'Kimhye', '5-1', '1st Voted Out Day 3']
SQL:

assistant: SELECT "Vote" FROM "Table" WHERE "Immunity" = 'David' AND "Reward" = 'None';