You will have to specify whether you are talking about a "European" or "American" roulette wheel. The standard European wheel has 32 numbers, red and black, together with "0" that is typically green. The standard American wheel has 32 numbers plus "0" and "00". That is the probability of a single turn coming up a specific number on a European wheel is 1/33, on an American wheel, 1/34. If you select 6 numbers, the probability of NOT getting a number in that group on one spin is 27/33= 9/11 on a European wheel, 28/34= 14/17 on an American wheel.
The probability of n spins without getting a number in your set of 6 is [tex](9/11)^n[/itex] on a European wheel, [itex](14/17)^n[/itex] on an American wheel. You need to solve [itex](9/11)^n= 0.01[/itex] or [itex](14/17)^n= 0.01[/itex].[/tex]