คู่ต่อสู้ในเบลเกรดคือใครและสกอร์ 5:2?
Who was the opponent in Belgrade and had a result of 5:2?
df = pd.DataFrame(columns=['opponent', 'city', 'results']), pd.to_numeric(df['results'], errors='coerce').fillna(0)
df[(df['city'] == "belgrade") & (df['results'] == 5.2)]['opponent']