I pulled up a 2017 Form 1040. at the bottom of the front page, line 35, there is a line that specifies "Domestic production activities deduction.  Attach Form 8903. 

In 2018 Schedule 1, there is no specific line for Domestic Production Activities Deduction.  I'd say someone at the IRS made a boo-boo when developing these Schedules.  Maybe I am wrong, but that is what it looks like to me. 

On a side note.... I don't know how you are filling out your forms.   On the IRS website,  there is free fillable forms.  Scroll down and you can see "Income above 66,000 Free Fillable Forms." I don't know if you have used this or not. I thought I would mention it.