user: Question: How many parties received 29.9% of the vote in Manhattan?
Columns: ['1921', 'party', 'Manhattan', 'The Bronx', 'Brooklyn', 'Queens', 'Richmond [Staten Is.]', 'Total', '%']
Types: ['text', 'text', 'text', 'text', 'text', 'text', 'text', 'real', 'text']
Sample row: ['John Francis Hylan', 'Democratic', '261,452', '118,235', '260,143', '87,676', '22,741', 750247.0, '64.2%']
SQL:

assistant: SELECT COUNT("party") FROM "Table" WHERE "Manhattan" = '29.9%';