user: Question:  how many party with incumbent being Whitmell P. Martin
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Louisiana 1', "James O'Connor", 'Democratic', 1918.0, 'Re-elected', "James O'Connor (D) Unopposed"]
SQL:

assistant: SELECT COUNT("Party") FROM "Table" WHERE "Incumbent" = 'Whitmell P. Martin';