I am preparing a dough with all purpose flour, salt, sugar, oil, curd, lemon juice and baking soda. I am not using baking powder. Within how much time should I complete my baking to reap maximum benefit of the leavening effect? I know that dough with baking soda needs to be cooked sooner, but is there any specific time that my baking should be completed?
No, there is no such time. The formulation you used, "needs to be baked sooner" is indeed the correct one. If you bake it without any delay, it will be better (the baking soda will have more effect) than if you delay for one minute. If you delay one minute, it will be better than when delayed two minutes. And so on.
At the other end, there will be a moment at which the baking soda turns from having almost-no-effect to having absolutely no effect at all. But since nobody would want to eat the food even if the soda had next-to-no-effect, trying to predict this moment is not really relevant to cooking.