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_name_56 ( primary_conference VARCHAR, ihsaa_football_class VARCHAR, school VARCHAR )

### Question ###
What is the primary conference with a IHSAA Football Class of A, at South Decatur school?

### Accurate SQL ###

SELECT primary_conference FROM table_name_56 WHERE ihsaa_football_class = "a" AND school = "south decatur"