you cannot get multiple columns from a single subquery have to change your query like this
(select * from
(select FCourseID , FCourseName ,FCourseDuration
from TCourse
where FCourseDuration in
(select MAX(FCourseDuration) as dd from TCourse )
) T
) AS DD
)
(select FCourseID
from TCourse
where FCourseDuration in
(select MAX(FCourseDuration) as dd from TCourse )
) T AS FCourseID
(select FCourseName
from TCourse
where FCourseDuration in
(select MAX(FCourseDuration) as dd from TCourse )
) T AS FCourseName,
(select FCourseDuration
from TCourse
where FCourseDuration in
(select MAX(FCourseDuration) as dd from TCourse )
) T AS FCourseDuration
hope it helps