Translate the following question to SQL: Find the names of departments that are located in Houston.

Schema: CREATE TABLE works_on (
    Essn INTEGER   PRIMARY KEY,
    Pno INTEGER   PRIMARY KEY,
    Hours REAL,
    PRIMARY KEY (Essn, Pno),
    UNIQUE (Essn, Pno)
);

CREATE TABLE employee (
    Fname TEXT,
    Minit TEXT,
    Lname TEXT,
    Ssn INTEGER   PRIMARY KEY,
    Bdate TEXT,
    Address TEXT,
    Sex TEXT,
    Salary INTEGER,
    Super_ssn INTEGER,
    Dno INTEGER
);

CREATE TABLE department (
    Dname TEXT,
    Dnumber INTEGER   PRIMARY KEY,
    Mgr_ssn INTEGER,
    Mgr_start_date TEXT
);

CREATE TABLE project (
    Pname TEXT,
    Pnumber INTEGER   PRIMARY KEY,
    Plocation TEXT,
    Dnum INTEGER
);

CREATE TABLE dependent (
    Essn INTEGER   PRIMARY KEY,
    Dependent_name TEXT   PRIMARY KEY,
    Sex TEXT,
    Bdate TEXT,
    Relationship TEXT,
    PRIMARY KEY (Essn, Dependent_name),
    UNIQUE (Essn, Dependent_name)
);

CREATE TABLE dept_locations (
    Dnumber INTEGER   PRIMARY KEY,
    Dlocation TEXT   PRIMARY KEY,
    PRIMARY KEY (Dnumber, Dlocation),
    UNIQUE (Dnumber, Dlocation)
);
user
SELECT t1.dname FROM department AS t1 JOIN dept_locations AS t2 ON t1.dnumber  =  t2.dnumber WHERE t2.dlocation  =  'Houston'
assistant