Conditions for 2 columns in DF to get the 3 column

I would like to make an IF condition to set the value in a new column ('new_col'). General idea is like:

if 'Score' = np.nan & 'Year' = 2012: return 1

elif 'Score' == np.nan & 'Year' = 2013: return 2

else: return 'Score'

data = {'year': [2010, 2011, 2012, 2013, 2014], 'Score': [10, 15, np.nan, np.nan, 3]}
df = pd.DataFrame(data, columns = ['year', 'Score'])



  year  Score
0  2010   10.0
1  2011   15.0
2  2012    1.0
3  2013    2.0
4  2014    3.0