user: Question: How many different set of candidates were there when the incumbent was David E. Finley?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['South Carolina 1', 'Richard S. Whaley', 'Democratic', '1913 (special)', 'Re-elected', 'Richard S. Whaley (D) 95.4% J. O. Ladd (R) 4.6%']
SQL:

assistant: SELECT COUNT("Candidates") FROM "Table" WHERE "Incumbent" = 'David E. Finley';