Three goals without reply seems difficult for Bochum to catch in the second match, so my prediction is that Fortuna Dusseldorf will move up a division and Bochum will be relegated.
Bochum was only able to control possession of the ball but their chances and finishing were quite poor compared to Dusseldorf, Bochum needs four goals without conceding if they want to stay in this division in the second match but that chance is quite small, maybe Bochum can wins the second match but still loses in aggregate goals, I don't see any chance for Dusseldorf to lose with a margin of more than three goals so they fail to move up the division.
Both teams come with different ambitions, Bochum who come from the Bundesliga because they are at the bottom of the table & Fortuna Dusseldorf who come from the 2. Bundesliga and are full of ambition. That's what differentiates these two teams. I think there's no longer any chance for Bochum to catch up, the most reasonable result in the second leg is Bochum winning, but they will not go to the Bundesliga.