NaHCO3 = sodium bicarbonate = baking soda
Na2CO3 = sodium carbonate = baking powder
Well, yes and no. For cleaning, it wouldn't make any difference. You're basically using the abrasive property of the undissolved solid.
In swimming pools you're using it to raise the pH of the water and both will work fine for that.
NaHCO3(s) --> Na+ + HCO3-
HCO3- + HOH <==> H2CO3(?) + OH-
.... there's no H2CO3 in aqueous solution, it's CO2(aq) and H3O, so drop the H2O in the following equation ...
HCO3- + HOH <==> H2O + CO2(aq) + OH-
.... and we get the following:
HCO3- <==> CO2(aq) + OH-
NaHCO3(s) <==> Na+ + CO2(aq) + OH-
Na2CO3(s) + HOH <==> 2Na+ + HCO3- + OH-
Na2CO3(s) + HOH <==> 2Na+ + CO2(aq) + 2OH-
In cooking there is a difference. They are not interchangeable. Sodium bicarbonate decomposes at a low temperature to make sodium carbonate, carbon dioxide and water vapor. Sodium carbonate decomposes at a very high temperature, much higher than your oven.
2NaHCO3(s) --heat--> Na2CO3(s) + CO2(g) + H2O(g)
The CO2 bubbles in the cake or bread or whatever provide the little holes and the lightness of the baked goods. Without the CO2 you would have unleavened bread which is very dense and has no holes.
======= Follow up =========
Skywolf X did not read that wikipedia article carefully. The pKa of NaHCO3 is 6.3, not the pH.
Here's the quote: "It has a pKa of 6.3 in water which causes aqueous solutions to be mildly alkaline." Solutions of BOTH sodium carbonate and sodium bicarbonate are basic.