user: Question: Attendance of 23,150 had what opponent?
Columns: ['Date', 'Opponent', 'Score', 'Loss', 'Attendance', 'Record']
Types: ['text', 'text', 'text', 'text', 'text', 'text']
Sample row: ['September 1', '@ Nationals', '7–4', 'Kendrick (11–8)', '28,393', '75–63']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Attendance" = '23,150';