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_204_133 ( id number, "school year" text, "class a" text, "class aa" text, "class aaa" text, "class aaaa" text, "class aaaaa" text )

### Question ###
which school won class a in the season previous to 1999-2000 ?

### Accurate SQL ###

SELECT "class a" FROM table_204_133 WHERE id = (SELECT id FROM table_204_133 WHERE "school year" = '1999-2000') - 1