You actually just need to reverse the first two arguments in the Lookup
expression:
=LookUp(1,Fields!Row.Value,Fields!Title.Value,"Titles")
=LookUp(2,Fields!Row.Value,Fields!Title.Value,"Titles")
=LookUp(3,Fields!Row.Value,Fields!Title.Value,"Titles")
.
.
With Lookup
, the first argument is the value that is being used to search in the specified DataSet; the second argument is the expression that will be applied to the Dataset and used to match the first argument.
So in your original expressions using Fields!Row.Value
as the first argument will always return 1, i.e. the first row in the Dataset, and as such it matches only one of the constant values.
Reversing these as above should get it going.