user: Question: what's the party with opponent being Mike Oxley (R) unopposed
Columns: ['District', 'Incumbent', 'Party', 'First elected', 'Status', 'Opponent']
Types: ['text', 'text', 'text', 'real', 'text', 'text']
Sample row: ['Ohio1', 'David S. Mann', 'Democratic', 1992.0, 'Defeated Republican gain', 'Steve Chabot (R) 56.1% David S. Mann (D) 43.9%']
SQL:

assistant: SELECT "Party" FROM "Table" WHERE "Opponent" = 'Mike Oxley (R) unopposed';