CREATE TABLE region (region_id NUMBER, region_name CLOB, date CLOB, label CLOB, format CLOB, catalogue CLOB)
CREATE TABLE member (member_id NUMBER, member_name CLOB, party_id CLOB, in_office CLOB)
CREATE TABLE party (party_id NUMBER, minister CLOB, took_office CLOB, left_office CLOB, region_id NUMBER, party_name CLOB)
CREATE TABLE party_events (event_id NUMBER, event_name CLOB, party_id NUMBER, member_in_charge_id NUMBER)

Which member names are shared among members in the party with the id 3 and the party with the id 1?
SELECT member_name FROM member WHERE party_id = 3 INTERSECT SELECT member_name FROM member WHERE party_id = 1
SELECT "member_name" FROM "member" WHERE "party_id" = 3 INTERSECT SELECT "member_name" FROM "member" WHERE "party_id" = 1