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_203_721 ( id number, "school" text, "location" text, "control" text, "type" text, "enrollment" number, "founded" number )

### Question ###
what is the difference in enrollment between the top 2 schools listed in the table ?

### Accurate SQL ###

SELECT ABS((SELECT "enrollment" FROM table_203_721 WHERE id = 1) - (SELECT "enrollment" FROM table_203_721 WHERE id = 2))