ระบุรหัสพื้นที่ที่ผู้ลงคะแนนโหวตให้ทั้งผู้เข้าแข่งขัน 'Tabatha Gehling' และผู้แข่งขัน 'Kelly Clauss'
List the area codes in which voters voted both for the contestant 'Tabatha Gehling' and the contestant 'Kelly Clauss'.
votes = pd.DataFrame(columns = ['contestant_number', 'state']); contestants = pd.DataFrame(columns = ['contestant_number', 'contestant_name']); area_code_state = pd.DataFrame(columns = ['area_code', 'state'])
area_code_state[area_code_state['state'].isin(votes[votes['contestant_number'].isin(contestants[contestants['contestant_name'].isin(['Tabatha Gehling', 'Kelly Clauss'])]['contestant_number'])]['state'])]['area_code']