user: Question:  how many incumbent with district  being Tennessee 5
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Tennessee 1', 'Jimmy Quillen', 'Republican', 1962.0, 'Re-elected', 'Jimmy Quillen (R) 71.7% Arthur Bright (D) 28.3%']
SQL:

assistant: SELECT COUNT("Incumbent") FROM "Table" WHERE "District" = 'Tennessee 5';