If you want a single row to return then you can do it alternatively using TOP clause.
SELECT TOP 1 Id, item_code, item_name, item_price, StockInHand, actv_code, actv_name
FROM Stocks
ORDER BY Id
If you want minimum id with same item_code then you can try something like-
SELECT S.Id, S.item_code, item_name, item_price, StockInHand, actv_code, actv_name
FROM Stocks S
INNER JOIN
(
SELECT MIN(Id), item_code
FROM Stocks
GROUP BY item_code
) AS T
ON S.Id=T.Id
If you want something else than this, please let me know.
Hope, it helps :)