ใครคือผู้ชนะสเตจที่ 9 เมื่อประเภททั่วไปคือดานิโล ดิ ลูก้า?
Who was the winner of Stage 9 when then general classification was Danilo Di Luca?
df = pd.DataFrame(columns=['winner', 'general_classification', 'stage'])
df.loc[(df['general_classification'] == 'danilo di luca') & (df['stage'] == '9'), 'winner']