Distributions should be reported in the year they are actually made. For your 2016 return, if those distributions were actually made during 2017, then they should be reported on this year's return. If these distributions were made in 2016, then they were reported correctly and you shouldn't enter the amounts again.
The software will keep track of the past activity, as long as you transfer your tax file each year. If no distributions of any kind were made to partners, then you shouldn't enter any amount here.
For this info at the IRS, see the instructions here: https://www.irs.gov/pub/irs-pdf/i1065.pdf
