What's the Student Body with an Affiliation of Roman Catholic and has an Enrollment of 502?
CREATE TABLE "private_schools" (
  "school" text,
  "grades" text,
  "affiliation" text,
  "student_body" text,
  "enrollment" real
);
SELECT "student_body" FROM "private_schools" WHERE "affiliation"='roman catholic' AND "enrollment"=502;