"I used to pursue my drawing hobby" is correct. The other sentence is correct, but awkward, and not something a native English speaker would say. You could also say... "I used to draw as a hobby" "I used to like drawing" "I liked drawing when I was younger but I didn't really have the talent so I gave it up"

The first sentence is better. In the second, the form of “my hobby of drawing” is more correct than “in drawing” but the first sentence is still more appropriate.