CREATE TABLE table_45718 ("Week" FLOAT, "Date" CLOB, "Opponent" CLOB, "Result" CLOB, "Attendance" FLOAT)

Which Week has a Result of w 20-13?
SELECT AVG("Week") FROM table_45718 WHERE "Result" = 'w 20-13'
SELECT AVG("Week") FROM "table_45718" WHERE "Result" = 'w 20-13'