CREATE TABLE table_26986076_6 (sat_21_aug VARCHAR(255), thurs_26_aug VARCHAR(255))
What was the Sat 21 Aug time for the driver whose Thurs 26 Aug time was 20' 56.01 108.143mph?
    
SQL: SELECT sat_21_aug FROM table_26986076_6 WHERE thurs_26_aug = "20' 56.01 108.143mph"