I found the problem but I don’t know how to solve it!?
Columnlength field does not exist on Pimcore 5 any more!!!
When i try to resave the Class I get the following error:
pimcore.ERROR: An exception occurred while executing ‘ALTER TABLE
Serievarchar NULL;’: SQLSTATE: Syntax error or access violation: 1064 You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near ‘NULL’ at line 1  
When I delete this select field(Serie) then it is no problem to resave the class and I can Listing the items as well.
BUT the problem is when I recreate the select field(Serie) I do not get back the data for the field and it is gone!
Any help please!