What a sad day for music.
Donald was an unsung hero- his beautiful, minimal, melodic Basslines pushed forward hundreds of classic Stax tunes and he's played with so many great musicians you'd be hard pressed to list them all.
As a budding Bassist, I'd listen to those great lines he wrote and try to copy them - the patterns were simple, but getting them to groove and flow the way Duck did was pretty near impossible. As a Bass teacher a few years later, I'd always get my students to listen to his lines- no wasted notes, no 'party tricks', just rock solid, meaty and melodic playing. I'm still using him as the template for many of the things I do and I'm not alone.
One of the greats.
"Time is Tight" by Booker T and The MGs featuring Duck and Al Jackson (Drums)