user: Question: Name the incumbent for first elected 1956
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['South Carolina 1', 'L. Mendel Rivers', 'Democratic', 1940.0, 'Re-elected', 'L. Mendel Rivers (D) Unopposed']
SQL:

assistant: SELECT "Incumbent" FROM "Table" WHERE "First elected" = 1956.0;