Refer below query :
SQL Query
CREATE TABLE #temp(Number VARCHAR(15))
CREATE TABLE #temp1(Digits VARCHAR(15))
INSERT INTO #temp VALUES('924-852132-200')
INSERT INTO #temp VALUES('927-856985-200')
INSERT INTO #temp1 VALUES('927-856985-200')
INSERT INTO #temp1 VALUES('927-856985-100')
INSERT INTO #temp1 VALUES('927-12360-400')
SELECT * FROM #temp
SELECT * FROM #temp1
SELECT 1 [COUNT]
,(SELECT TOP 1 #temp1.Digits FROM #temp1 )
FROM #temp INNER JOIN #temp1 ON #temp.Number = #temp1.Digits
WHERE SUBSTRING(#temp.Number,0,12) = SUBSTRING(#temp1.Digits,0,12)
GROUP BY #temp1.Digits
DROP TABLE #temp
DROP TABLE #temp1
Screenshot
Explanation: In below output you can see temporary table temp#1 contains two records matches first row of temporary table #temp as per your requirement, also query is returning only first match as well.