ValueError: time data does not match format '%H:%M:%S.%f' (match)

Question

I have a dataframe with thousand of rows

df_11=

     dataReceived      time     
0       1           15:00:56.052554
1       1           15:02:18.764644
2       1           02:43:10 
3       1           05:46:12
...
6054    1           23:15:14.5687

When i'm trying to convert the column time into date time like this:

pd.to_datetime(df_11['time'], format='%H:%M:%S.%f')

I got the obvious error:

ValueError: time data '02:43:10' does not match format '%H:%M:%S.%f' (match)

Is their a way to easyly append .0 to certains values to fulfill the criteria? I think it's the best thing to do here

I found this similar problem here but i'd like to not use loop when working with dataframe

thx