user: Question: How many candidates were there when Henry Garland Dupré was the incumbent? 
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("Candidates") FROM "Table" WHERE "Incumbent" = 'Henry Garland Dupré';