Pretty sure that's a Ducati Rolly.
Single speed, two stroke, 50cc, top speed 50kph. Made in 1968, both in Italy and Spain where Mototrans made them. In 1969, Mototrans produced a slightly different, home market version called 'El Junior' - but I
think that's a Rolly.
Always willing to be proven wrong, tho' ...
Here's another one:
And a brochure shot:
Vroom, vrooom. Should give one to Valentino for his paddock bike ...
Ciao
Craig