What is the lowest Frequency where the Hemholtz pitch is d?
CREATE TABLE table_77930 (
    "String" text,
    "Scientific pitch" text,
    "Helmholtz pitch" text,
    "Interval from middle C" text,
    "Frequency ( Hz )" real
)
SELECT MIN("Frequency ( Hz )") FROM table_77930 WHERE "Helmholtz pitch" = 'd'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: What is the lowest Frequency where the Hemholtz pitch is d? ### Input: CREATE TABLE table_77930 (
    "String" text,
    "Scientific pitch" text,
    "Helmholtz pitch" text,
    "Interval from middle C" text,
    "Frequency ( Hz )" real
) ### Response: SELECT MIN("Frequency ( Hz )") FROM table_77930 WHERE "Helmholtz pitch" = 'd'