user: Question: Who were the incumbent(s) in the election featuring  John Murray (DR) 50.4% George Denison (DR) 49.6% with a result of a Retired Democratic-Republican hold?
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Result', 'Candidates']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['Pennsylvania 8', 'Alexander Ogle', 'Democratic-Republican', '1816', 'Retired Democratic-Republican hold', 'Robert Philson (DR) 59.6% John A. Bard (F) 40.4%']
SQL:

assistant: SELECT "Incumbent" FROM "Table" WHERE "Candidates" = 'John Murray (DR) 50.4% George Denison (DR) 49.6%' AND "Result" = 'Retired Democratic-Republican hold';