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_45357 ( "Team" text, "Tries for" text, "Tries against" text, "Try diff" text, "Points for" text, "Points against" text, "Points diff" text )

### Question ###
What is Tries Against, when Tries For is 20?

### Accurate SQL ###

SELECT "Tries against" FROM table_45357 WHERE "Tries for" = '20'