How do I display another column Value in WebI instead of the Max Value using Max() Function?

Hi, my data is like below:

In details, I have two projects, A and B, and each project has its respective tasks.

My Goal: Display the Task that took longest to run.

What I want:

Project
Max Duration
Task Taking the Longest Duration
Project A 5 Task 1 Project B 8 Task 2

What I have (when i show the details)

[Max Duration] = Max([Duration]) in ([Project])

[Task Taking the Longest Duration] = [Task] where ([Duration] = [Max Duration])

Project
Task
Duration
Max Duration
Task Taking the Longest Duration
Project A Task 1 5 5 Task 1 Project A Task 2 1 5
Project A Task 3 2 5
Project B Task 1 4 8
Project B Task 2 8 8 Task 2

What I get instead when i remove the detail columns Task and Duration:

Project
Max Duration
Task Taking the Longest Duration
Project A 5 #MULTIVALUE Project B 8 #MULTIVALUE

Please help, I do not understand why is it displaying #multivalue when all my other values are empty "".