Prueba esto:
declare @s varchar(50) = '1,A;2,B;3,C'
--convert string to xml table (I used HTML tags for clarity)
declare @xml xml = cast('<tr><td>' + replace(replace(@s, ';', '</td></tr><tr><td>'), ',', '</td><td>') + '</td></tr>' as xml)
--query the xml to get SQL table
select tbl.col.value('td[1]', 'int') [ID],
tbl.col.value('td[2]', 'varchar(10)') [Text]
from @xml.nodes('/tr') tbl(col)
Para obtener más información:Convert Xml to Table SQL Server
