Question on Box 13 on K-1 (partnership). I have an amount for "deductions - portfolio (2% floor)" Do I input that into Box 13-L ("Deductions-portfolio (other)"

No, the code 13L is for deductions that are not subject to the 2% income limitation.  Because the designation "2% floor", you will use code W Other Deductions.

Prior to 2018 these "2% floor" portfolio deductions went to Schedule A as an itemized deduction subject to the 2% of adjusted gross income threshold.  Starting in 2018 these were no longer deductible on the federal tax return, but may be an itemized deduction on your state tax return.