How do you find the simplest ratio between the numbers of moles of NaHCO3 and CO2?

Mole ratio NaHCO₃ : CO₂
= 0.0333 : 0.0643
= (0.0333/0.0333) : (0.0643/0.0333) …… divided by the smallest number
≈ 1 : 2

divide both by whichever is smallest.  This forces 1 of the values to = 1 and the other to be > 1, which makes things easier to see.  We can do this because we only care about the ratios and not the absolute values

in this case, 0.0333 < 0.0643 so we divide both by 0.0333
.. mole NaHCO3 = 0.0333 / 0.0333 = 1
.. mole CO2 = 0.0643 / 0.0333 = 1.93 ~ 2

therefore the ratio is 1:2

I'm not at all certain what you are doing, but if you want to just find the ratio of moles of one to the other, just divide one number of moles by the other one. If you divide:
moles CO2 / moles NaHCO3 = 0.0643/0.0333 = 1.93

I'm not sure what that tells you, though, since you don't say anything about where these numbers come from.

Normally, if you decompose NaHCO3 to form CO2, the possible reactions are:By heating: NaHCO3 --> NaOH + CO2 or
By adding an acid: NaHCO3 + HCl --> NaCl + H2O + CO2

In both cases, you would expect to see a 1:1 mole ratio between NaHCO3 and CO2.