python split column into multiple columns but keep the other column code example

Example: How to split a text column into two separate columns?

import pandas as pd 

df = pd.DataFrame(["STD, City    State",
"33, Kolkata    West Bengal",
"44, Chennai    Tamil Nadu",
"40, Hyderabad    Telengana",
"80, Bangalore    Karnataka"], columns=['row'])

out = pd.DataFrame(df.row.str.split(' ',2).tolist(),columns=['STD','City','State'])
out.drop(index=0,inplace=True)