I've found for myself that my overall carb intake is much more important than any food's specific carb content, at least for each meal or snack. I don't use low-carb catsup, but I'm very careful with it.
As for pasta sauces, I'm MUCH more careful with pasta sauces because some of the regular pasta sauces are insanely high in sugar. I don't buy pasta sauces advertised as "low carb" because they're usually insanely expensive, and I can usually find a "regular" sauce that is as low in carbs, or nearly so. And if I can't find a low-carb sauce, I'll make my own from tomato puree and petite diced tomatoes (checking both for added sugar in the ingredient lists).
I use a lower carb exchange plan to control my calories and carbs, so in theory I could eat all my carbier foods in one meal. And I have done that. It doesn't change my weight loss, but it does make it much harder to stay on plan (because without fat and protein to "balance" the meal or snack, "straight" carbs, even the healthy ones, make me hungrier - sometimes hungrier than not eating at all. The more carbs I eat, the hungrier I get).
Some people say they do notice less loss when they eat even small amounts of higher-sugar foods, so you'll have to experiment.