CREATE TABLE table_64114 ("Week" FLOAT, "Date" TEXT, "Opponent" TEXT, "Result" TEXT, "Attendance" FLOAT)

What is the week with w 31-21 result?
SELECT "Week" FROM table_64114 WHERE "Result" = 'w 31-21'
SELECT "Week" FROM "table_64114" WHERE "Result" = 'w 31-21'