Table schema:
CREATE TABLE votes (contestant_number VARCHAR, state VARCHAR); CREATE TABLE contestants (contestant_number VARCHAR, contestant_name VARCHAR); CREATE TABLE area_code_state (area_code VARCHAR, state VARCHAR)

Question: List the area codes in which voters voted both for the contestant 'Tabatha Gehling' and the contestant 'Kelly Clauss'.
SQL: SELECT T3.area_code FROM contestants AS T1 JOIN votes AS T2 ON T1.contestant_number = T2.contestant_number JOIN area_code_state AS T3 ON T2.state = T3.state WHERE T1.contestant_name = 'Tabatha Gehling' INTERSECT SELECT T3.area_code FROM contestants AS T1 JOIN votes AS T2 ON T1.contestant_number = T2.contestant_number JOIN area_code_state AS T3 ON T2.state = T3.state WHERE T1.contestant_name = 'Kelly Clauss'