When singer, songwriter and SiriusXM radio host Paula Nelson mentioned to her friend Bruce Robison that she wanted to record some of her dad’s songs, he invited her — and her dad, Willie — to the Bunker, his all-analog recording studio in Lockhart, Texas, where he wound up producing a pair of father-daughter duets. Robison’s label, The Next Waltz, will release the first one, “Slow Down Old World,” on Feb. 24.