Question: Who were the candidates when Henry Garland Dupré was incumbent?
SQL: SELECT "Candidates" FROM "1-1342451-16" WHERE "Incumbent" = 'Henry Garland Dupré';

Question: How many candidates were there when Henry Garland Dupré was the incumbent? 
SQL: SELECT COUNT("Candidates") FROM "1-1342451-16" WHERE "Incumbent" = 'Henry Garland Dupré';

Question: What district did James O'Connor belong to?
SQL: SELECT "District" FROM "1-1342451-16" WHERE "Incumbent" = 'James O''Connor';