user: Question: What party was Re-elected as an incumbent of Robert P. Kennedy?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result']
Types: ['text', 'text', 'text', 'text', 'text']
Sample row: ['Ohio 1', 'Benjamin Butterworth', 'Republican', '1884', 'Re-elected']
SQL:

assistant: SELECT "Party" FROM "Table" WHERE "Result" = 'Re-elected' AND "Incumbent" = 'Robert P. Kennedy';