# import necessary libraries
import pandas as pd

# create a dataframe
df = pd.DataFrame({'A': [1, 2, 3], 'B': [4, 5, 6], \
                    'C': [7, 8, 9], 'D': [10, 11, 12]})

# find row, col number of value 6 in B column
row = df.loc[df['B'] == 6].index[0]
col = df.columns.get_loc('B')

# print the results
print('Row:', row)
print('Column:', col)