What is the primary conference that was founded before 1866 and has an affiliation of private/catholic?
CREATE TABLE "membership" (
  "school" text,
  "location" text,
  "founded" real,
  "affiliation" text,
  "enrollment" real,
  "nickname" text,
  "primary_conference" text
);
SELECT "primary_conference" FROM "membership" WHERE "founded"<1866 AND "affiliation"='private/catholic';