Try an OUTER APPLY
SELECT
C.Content_ID,
C.Content_Title,
C.Content_DatePublished,
M.Media_Id
FROM
tbl_Contents C
OUTER APPLY
(
SELECT TOP 1 *
FROM tbl_Media M
WHERE M.Content_Id = C.Content_Id
) m
ORDER BY
C.Content_DatePublished ASC
Alternatively, you could GROUP BY
the results
SELECT
C.Content_ID,
C.Content_Title,
C.Content_DatePublished,
M.Media_Id
FROM
tbl_Contents C
LEFT OUTER JOIN tbl_Media M ON M.Content_Id = C.Content_Id
GROUP BY
C.Content_ID,
C.Content_Title,
C.Content_DatePublished,
M.Media_Id
ORDER BY
C.Content_DatePublished ASC
The OUTER APPLY
selects a single row (or none) that matches each row from the left table.
The GROUP BY
performs the entire join, but then collapses the final result rows on the provided columns.