How to Select the First Element of a Series (Python)

I need to extract/clean the contents of a df (series), keeping only the first record (on the left) for each element between the parentheses.

I will put the current tables and how I need the information, as it makes it easier to observe the problem.

Current df:

Desired df:

Is this desired df possible?

>Solution :

Assuming the values of chords column are lists of tuples

df['chords'] = df['chords'].map(lambda lst: ", ".join(tup[0] for tup in lst))