Yes, it should also be correct because present tense in Italian can be used to describe an ongoing action in the present.
Note that in Italian there is another tense, that is taught later in the skill tree, called gerund which is better equivalent of present continuous. If we use gerund : "They are drinking coffee after lunch." = "Stanno bevendo caffè dopo pranzo."
btw Italian present tense can be translated into English in several ways, depending on the intended meaning: http://italian.about.com/od/verbs/a/italian-verbs-present-tense.htm
I'm not an expert on what the contexts are, but:
In English there are contexts where you'll use or not use the definite article, and using it or not will either change the meaning or make it ungrammatical. The same general principles apply in Italian, although the rules themselves are not all the same.