how to get particular row at first

Posting this solution as another has already been posted but I think an alternative might be required.

At first sight it looks as if you just want the table to be ordered by column [a] in which case you need (nod to @hypermellow)

select a, b, c from [table] order by a

which will produce

1 mass 32
2 seed 10
3 kadd 12
4 ssds 55

However your wording

Quote:

how to get particular row at first remaining records in same order

suggests that you might want something like

with CTE AS (
    select a, b, c, 1 as rownum from [table] where b = 'mass'
    UNION ALL
    select a, b, c, 1 + ROW_NUMBER() OVER (ORDER BY b)
    FROM [table] where b <> 'mass'
)
SELECT a, b, c FROM CTE order by rownum

which will produce results

1	mass	32
3	kadd	12
2	seed	10
4	ssds	55

The point of interest here is that I have manually assigned a rownum of 1 to the record I want first, then allowed sql to generate row numbers for me based on whichever order is required (I used column [b] just to highlight the difference) - note that I add 1 to the generated row number to ensure the sub-query doesn't end up with a rownum=1 to clash with my first query.
I then just UNION the two queries.

If you did only want a single record returned (in either case) then use TOP 1 as suggested by Amaan23 (but your wording implies that this is not what you want)