Selecting a part of text from 1 column and put this in a new column

I need to put a part of a text from a column and place it in a new collumn. At this moment I use 2 columns and an extra sheet to solve this.

I have a collumn with a lot of data like:

aaa-bc
bbb
abc-ba-bd
aa-bb
bbb-xx-yy
aa
abc-yy
klmn-zz
klmn-yy-ff

What I need is behind every cell a new cell with only the 1st part like:

aaa
bbb
abc
aa
bbb
aa
abc
klmn
klmn

What I do now is use a new column with this formula:

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And I made a translation table in which the 1st 4 characters are translated to what I want to see. In a 3d column I use

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to get the results I need.
Since I need to get results like this very often this method is very time consuming.

Is there a formula available I can use with only 1 new column?

Please try this function

=IFERROR(SUBSTITUTE(LEFT(A1,FIND("-",A1)),"-",""),A1)

Works as needed! Thanks al lot!