user: Question: How many candidates were elected in the Louisiana 4 district?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Louisiana 1', 'F. Edward Hebert', 'Democratic', 1940.0, 'Re-elected', 'F. Edward Hebert (D) Unopposed']
SQL:

assistant: SELECT COUNT("First elected") FROM "Table" WHERE "District" = 'Louisiana 4';