Inter Milan still has a chance to take the top spot in the table. Because Inter Milan has played 1 match less than Napoli and is 3 points behind. If Inter Milan can win their next match, then Inter Milan will take the top spot in the table.
Inter Milan can top the table if they win their uncompleted match, but they will be topping by goal difference since they can only succeed to equal points with Napoli. Taking the top spot from Napoli will not mean anything until if they are able to top the table by some points difference instead of just an ordinary goal difference.
Although Napoli is at the top of the table, the overall performance of this team is not very strong. We saw Napoli's poor performance against Roma. Also, Napoli's attack is not strong enough. Napoli's players have scored 38 goals in 23 matches. On the other hand, Inter Milan has scored 56 goals in 22 matches. Napoli will not be able to hold on to the top spot in the table for long.
For the fact that Napoli drew against Roma in their last game do not mean that Napoli performed poorly or that their attack is not strong enough, it is normal for a consistent team to lose form at some point, but it doesn't mean that they performed poorly. Besides Napoli has met some big teams in the Serie A and won so i don't see a problem with the draw they got at Roma. Unless they lose points consecutively, we can then say that they are performing badly but for now, everything is under control for the team. Inter Milan has scored more goals than Napoli, but the most important thing is who will get most points and not most goals.