user: Question: Who's the incumbent of Indiana 4 district?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Indiana 1', 'Ray J. Madden', 'Democratic', '1942', 'Re-elected', 'Ray J. Madden (D) 58.3% Albert Harrigan (R) 41.7%']
SQL:

assistant: SELECT "Incumbent" FROM "Table" WHERE "District" = 'Indiana 4';