CERCLIS ID ของไซต์ใน Polk County คืออะไร ณ วันที่ 08/04/2009
What is the CERCLIS ID of the site in Polk County, with the date 08/04/2009?
df = pd.DataFrame([], columns=['cerclis_id', 'county', 'deleted'])
df[(df['county'] == 'polk') & (df['deleted'] == '08/04/2009')]['cerclis_id']