ฉันมีผู้ชนะกี่คนใน Dessau Autobahnspinne?
How many winners did I Dessau Autobahnspinne have?
df = pd.DataFrame(columns=['winning_driver', 'race_name'])
df[df['race_name'] == 'I Dessau Autobahnspinne']['winning_driver'].nunique()