Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_29204 ( "Rank" real, "Rider" text, "Sat 21 Aug" text, "Mon 23 Aug" text, "Tues 24 Aug" text, "Wed 25 Aug" text, "Thurs 26 Aug" text, "Fri 27 Aug" text, "Sat 28 Aug" text )

### Question ###
What was the Sat 21 Aug time for the rider whose Tues 24 Aug time was 20' 38.40 109.680mph?

### Accurate SQL ###

SELECT "Sat 21 Aug" FROM table_29204 WHERE "Tues 24 Aug" = '20'' 38.40 109.680mph'