Discussions of the passive voice often cause more confusion than they avoid. It is always easier to see your way clear in these cases if you think in terms of naming or hiding the agent. In other words:
Tom kicked the dog.
Here the agent is named. We know who did the kicking.
The dog was kicked.
Here the agent is concealed. We do not know who did the kicking.
The question here is, does it matter who kicked the dog? In this case it probably does, so we should choose a form that names the agent. That form also happens to be active voice, but we can ignore that as a grammatical technicality.
There is a form that names the agent and is also passive voice:
The dog was kicked by Tom.
Which is better between this and the first sentence? This is not something that we should decide based on the first being active and the third passive. Rather, we should decide based on what is most important in the sentence. The first sentence is about Tom; the dog is incidental. The second sentence is about the dog; Tom is incidental. The choice depends on which we are more interested in, the dog or Tom. It is no kind of writing sin to be more interested in the recipient of an action than in its perpetrator.
Now in your case:
We display the values of X in Table 1.
This names the actor ("we"). Is there any purpose to naming the actor here? No. In fact, who else could the actor have been? (Certainly not that dastardly Tom). So naming the actor serves no purpose here. The actor is being named unnecessarily just to make the sentence active voice. And while this does no great harm, there is no reason at all to choose it over the alternative.