Table: match_results_6
Columns: date
opponents
h_a
result_f_a
scorers

Question: Who was the opponent when the H/A was H and the scorer was Ferguson?
SQL: SELECT "opponents" FROM match_results_6 WHERE "h_a" = 'h' AND "scorers" = 'ferguson'

Question: Who was the opponent on 11 August 1991 when the H/A was H?
SQL: SELECT "opponents" FROM match_results_6 WHERE "h_a" = 'h' AND "date" = '11 august 1991'

Question: What was the H/A when the scorer was Hughes?
SQL: SELECT "h_a" FROM match_results_6 WHERE "scorers" = 'hughes'