user: Question: How many of the first elected were listed when Hatton W. Sumners was incumbent and Re-elected?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Texas 2', 'John C. Box', 'Democratic', 1918.0, 'Re-elected', 'John C. Box (D) Unopposed']
SQL:

assistant: SELECT COUNT("First elected") FROM "Table" WHERE "Result" = 'Re-elected' AND "Incumbent" = 'Hatton W. Sumners';