I would say it's a Panasonic EVJ-Y dual potentiometer 12mm. Pic matches. Roland sticks with fellow Japanese manufacturers.
They are quite popular, but Digikey shows them as obsolete (EVJ-Y, EVJ-C) with some stock still, Mouser has them too.
You just have to find the taper (linear or logarithmic) and ohms value, and if there is a center-detent or not. Some are metal bushing, or plastic with sleeve, or no sleeve.