user: Question: What is the Opponent at the game with an Attendance of 64,900 in Week prior to 15 with a Result of L 38-31?
Columns: ['Week', 'Date', 'Opponent', 'Result', 'Attendance']
Types: ['real', 'text', 'text', 'text', 'text']
Sample row: [1.0, 'September 12, 2004', 'Seattle Seahawks', 'L 21-7', '64,900']
SQL:

assistant: SELECT "Opponent" FROM "Table" WHERE "Week" < 15.0 AND "Attendance" = '64,900' AND "Result" = 'L 38-31';