user: Question: What district is incumbent Elmer J. Holland from?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Pennsylvania 4', 'Herman Toll', 'Democratic', 1958.0, 'Re-elected', 'Herman Toll (D) 64.1% James R. Cavanaugh (R) 35.9%']
SQL:

assistant: SELECT "District" FROM "Table" WHERE "Incumbent" = 'Elmer J. Holland';