Table schema:
CREATE TABLE table_26986076_6 (sat_21_aug VARCHAR, tues_24_aug VARCHAR)

Question: What was the Sat 21 Aug time for the rider whose Tues 24 Aug time was 20' 38.40 109.680mph?
SQL: SELECT sat_21_aug FROM table_26986076_6 WHERE tues_24_aug = "20' 38.40 109.680mph"