หมายเลขตอนใดในซีรีส์ที่มีผู้ชม 2.528 ล้านคน?
What episode number in the series had 2.528 million u.s. viewers?
df = pd.DataFrame(columns=['no_in_series', 'us_viewers__in_millions_'])
df[df['us_viewers__in_millions_'] == "2.528"]['no_in_series']