I have no idea what "below row" means...
Assuming that you want to find next or previous values in a table, you can use:
LEAD[
^] or
LAG[
^] function.
See:
CREATE TABLE Components
(
ABC varchar(30),
[Level] int
);
INSERT INTO Components(ABC, [Level])
VALUES('1234Z2DD', 0), ('1234Z2DD',1),
('1234Z2DD',2), ('1234Z2DD',2),
('1234Z2DD',3), ('1234Z2DD',3),
('1234Z2DD',3), ('1234Z2DD',3),
('1234Z2DD',2), ('1234Z2DD',3),
('1234Z2DD',2), ('1234Z2DD',3),
('1234Z2DD',2), ('1234Z2DD',3),
('1234Z2DD',2), ('1234Z2DD',3),
('1234Z2DD',2), ('1234Z2DD',3),
('1234Z2DD',1), ('1234Z2DD',2),
('1234Z2DD',3), ('1234Z2DD',2),
('1234Z2DD',3), ('1234Z2DD',2),
('1234Z2DD',2), ('1234Z2DD',3),
('1234Z2DD',1), ('1234Z2DD',1),
('1234Z2DD',2);
SELECT ABC, [Level], Avail = CASE
WHEN [Level] = 0 THEN 'NA'
WHEN [Level] = 1 AND LEAD([Level]) OVER(ORDER BY ABC) > 1 THEN 'Available'
ELSE '' END
FROM COmponents;
SQL Server 2019 | db<>fiddle[
^]