Table: ludmannsdorf_slovenes
Columns: village_german
village_slovene
number_of_people_1991
percent_of_slovenes_1991
percent_of_slovenes_1951

Question: What was the percent of slovenes 1951 for bach?
SQL: SELECT "percent_of_slovenes_1951" FROM ludmannsdorf_slovenes WHERE "village_german" = 'Bach'