is this a scripting question?
If yes, would you like to use InDesign's GREP functionality or a simple RegExp statement on a string?
Does "Autor 1" stand for a variable that can hold any name?
Tell us more about the position of "Autor 1;" in the text flow.
Could it be everywhere? Or just at the beginning of a paragraph?
You can use a findGrep formula like
^.*?(?<=;) for including semicolon
^.*?(?=;) to match without semicolon
I suggest to run it with a selection as a target since this is very general condition (many matches possibly)
I would recommend to use nested paragraphStyle to keep this format in dynamic mode
use a condition: upto 1st occurrence of semicolon