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_52413 ( "Position" real, "Club" text, "Played" real, "Points" text, "Wins" real, "Draws" real, "Losses" real, "Goals for" real, "Goals against" real, "Goal Difference" real )

### Question ###
What is the average of goals against, where overall goals are more than 35 and the goal difference is 20?

### Accurate SQL ###

SELECT AVG("Goals against") FROM table_52413 WHERE "Goals for" > '35' AND "Goal Difference" = '20'