There is no standard report that includes resource demand by contract type.

You can create a Cognos report for this purpose. The Cognos data model does not include this data directly. However, you can use the Resource Demands > Project query subject and then join from the AssociatedId to the ProjectId from a custom SQL query that would look similar to the following:

Select p.ProjectId, e.ContractType
From Project p
Inner Join Engagment e on p.EngagementId = e.EngagementId