CREATE TABLE table_52231 ("Week" FLOAT, "Date" CLOB, "Opponent" CLOB, "Result" CLOB, "Attendance" CLOB)

On what date was the attendance of the crowd 78,431?
SELECT "Date" FROM table_52231 WHERE "Attendance" = '78,431'
SELECT "Date" FROM "table_52231" WHERE "Attendance" = '78,431'